alert http1 $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Dridex POST Retrieving Second Stage M2"; flow:established,to_server; http.host.raw; pcre:"/^(?=[a-z0-9]{0,19}[A-Z])(?:(?=[A-Z0-9]{0,19}[a-z])|(?=[A-Za-z]{0,19}\d)|(?=[A-Z]+\.))[a-zA-Z0-9]{3,20}[\x2e\x20][a-z]{2,3}$/"; http.start; content:"POST / HTTP/1.1|0d 0a|"; startswith; fast_pattern; http.request_body; byte_extract:1,4,Dridex.Pivot,relative; byte_test:1,!=,Dridex.Pivot,0,relative; byte_test:1,=,Dridex.Pivot,7,relative; pcre:"/^[\x20-\x7e\r\n]{0,20}[^\x20-\x7e\r\n]/R"; reference:md5,148112df459ba40b9127f7d4f1c08df2; classtype:trojan-activity; sid:2020825; rev:10; metadata:created_at 2015_04_01, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_14;)